Multi-Stable Compliant-Mechanism-Based Mattress for Bedsore Prevention

Abstract Pressure injuries (i.e., bedsores) affect 2.5 million Americans every year and 60,000 die from them. Although several commercial alternating-pressure and low air-loss mattress products already exist to address this scourge, these products are not optimally effective and lack the evidence to deserve a strong medical recommendation. Moreover, they are expensive, heavy, and loud, and can exhibit lack of air- permeation, air leakage issues, and round-the-clock power consumption. We propose a multi-stable compliant-mechanism-based (MSCMB) mattress to overcome these issues and optimally prevent prolonged levels of harmful pressure in the existing immobile and aging population. During Phase I of our current grant, which began May 1st, 2021, we successfully fabricated a bed that consists of 1,260 linear actuator pistons that can be controlled by a computer to impart any undulating pressure pattern on a patient’s back. By the end of Phase I (April 30th, 2022), we will have used this bed to complete a study, which involves machine learning to determine (i) what factors predominantly affect bedsore prevention in alternating pressure approaches, and (ii) what the optimal height of (i.e., amplitude) and distance between (i.e., pitch) each pressure peak should be for different categories of patients. We will use this information to inform the design of the final products that will be prototyped and perfected in Phase II. During Phase I, we also generated a MATLAB tool that was used to design a large portion of our proposed MSCMB mattress concept and have prototyped it to demonstrate its functionality and to collect preliminary data. The design tool and the lessons learned during the fabrication and testing of the prototype will be heavily leveraged in Phase II to successfully perform the proposed aims. These aims are to (i) create the final MSCMB mattress products that best reduce pressure injuries for different categories of patients, (ii) produce a smart phone app and a web-based computer software that can be used to remotely set the switching frequency of the actuated versions of the MSCMB mattress designs, (iii) conduct a study to identify the most effective kind and thickness of foam pad to use on top of each MSCMB mattress product, (iv) determine and perfect the final process for manufacturing the MSCMB mattresses, and (v) perform a user evaluation study of the MSCMB mattress products.